Flip-top preform for blow molding

ABSTRACT

A preform for blow molding a plastic container with a flip-top closure includes a container portion and a flip-top closure base portion integrally molded with the container portion. The flip-top closure base portion includes an integrally molded first hinge structure for connecting the flip-top closure base portion to a flip-top closure top to create the flip-top closure for the container.

CROSS REFERENCE

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/408,360, filed Oct. 29, 2010.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to the field of blow moldingplastic containers and, more particularly, to an improved preform forblow molding plastic containers.

BACKGROUND OF THE INVENTION

Injection blow molding is a commonly used manufacturing process forproducing hollow plastic parts from thermoplastic material. Injectionblow molding can be used to produce plastic containers, most frequentlysmall medical and single serve bottles. In general, the blow moldingprocess involves melting down a thermoplastic material and forming itinto a parison or preform. The perform is typically a tube-like piece ofplastic with a hole in one end to accommodate the introduction ofcompressed air. The preform is heated and a pressurized gas, usuallyair, is used to expand the hot preform and press it against the interiorof a mold cavity. The pressure within the preform is maintained untilthe plastic cools and solidifies in the desired shape at which time themold is opened to release the newly formed container.

In the past, finishing of a blow molded container, for example theaddition of closure structures, has occurred entirely in separate,subsequent operations. This is particularly true in the case ofcontainers using flip-top closures. The flip-top closure is molded orotherwise manufactured separately. It is then added to the already blowmolded container by any number of known means. An example of a prior artcontainer manufactured by the prior art method is provided in FIG. 1.While this method of assembly is widely used, it does require multiplemanufacturing steps and generally requires the use of a greater amountof plastic material than might otherwise be necessary. This latterquality in particular can be a significant drawback for projects wheresustainable manufacturing is a key metric.

Therefore, it would be advantageous to provide a means for improving theprocess for injection blow molding of containers and that addresses oneor more of the problems set forth above.

SUMMARY OF THE INVENTION

One aspect of the invention generally pertains to an improved preformfor producing blow-molded plastic containers.

Another aspect of the invention pertains to a preform for blow moldingplastic flip-top containers that reduces the amount of plastic requiredfor manufacturing.

In accordance with the above aspects of the invention, there is provideda preform for blow molding a plastic container with a flip-top closurethat includes a container portion and a flip-top closure base portionintegrally molded with the container portion. The flip-top closure baseportion includes an integrally molded first hinge structure forconnecting the flip-top closure base portion to a flip-top closure topto create the flip-top closure for the container.

In another embodiment, there is provided a method of blow molding aflip-top closure container that includes the steps of molding a preformwith a container portion and an integral flip-top closure base portion,wherein the flip-top closure base portion is integrally molded with afirst hinge structure to facilitate a mating engagement with a flip-topclosure top; inserting the preform into a blow mold; inflating thecontainer portion of the preform within the blow mold; and removing theinflated preform from the blow mold.

These aspects are merely illustrative of the innumerable aspectsassociated with the present invention and should not be deemed aslimiting in any manner. These and other aspects, features and advantagesof the present invention will become apparent from the followingdetailed description when taken in conjunction with the referenceddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is now made more particularly to the drawings, whichillustrate the best presently known mode of carrying out the inventionand wherein similar reference characters indicate the same partsthroughout the views.

FIG. 1 is a perspective view of a container with a flip-top closureproduced by the prior art blow molding process.

FIG. 2 is a perspective view of a preform according to an embodiment ofthe present invention.

FIG. 3 is a perspective view of a container with a flip-top closureproduced with a preform according to an embodiment of the presentinvention.

FIG. 3 is a perspective view of the container of FIG. 2 with theflip-top closure in the closed position.

FIG. 4 is a side view of the container of FIG. 2 with the flip-topclosure in the open position.

FIG. 5 is an alternate perspective view of the preform of FIG. 2.

FIG. 6 is a perspective view of the underside of an upper portion of aflip-top closure that may be used with the lower portion of the closureshown in FIGS. 2-5.

FIG. 7 is a perspective view of a preform according to an alternateembodiment.

DETAILED DESCRIPTION

In the following detailed description numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Forexample, the invention is not limited in scope to the particular type ofindustry application depicted in the figures. In other instances,well-known methods, procedures, and components have not been describedin detail so as not to obscure the present invention.

FIGS. 2-5 illustrate an embodiment of a preform 10 according to a firstembodiment of the present invention. The preform 10 includes a containerportion 12 and a closure base portion 14. The container portion 12 istube-shaped and hollow in order to be compatible with existing injectionblow molding equipment. The container portion 12 and closure baseportion 14 are co-molded together.

The closure base portion 14 is the lower half of a flip-top closure. Theclosure base portion has an outer skirt 16 and a central opening 18 thatcommunicates with the hollow interior of the container portion 12 of thepreform 10. Surrounding the central opening 18 is a slightly upwardlyextending collar 20. Surrounding the collar 20 is a generally flat,first horizontal surface 22. Outside of this first horizontal surface 22is a second surface 24 that lies slightly below the level of the firstsurface 22. The closure base portion 14 also includes a matching pair ofhinge members 26 extending upward from the upper surface of the closurebase portion 14. These hinge members 26 provide a convenient point ofattachment for the closure base portion 14 with a second portion of theclosure.

In the illustrated embodiment, there is also provided a depressed area28 in the outer skirt 16 between the hinge members 26. The depressedarea 28 coordinates with a tab on the second portion of the closure asdescribed below.

As shown in FIG. 5, opposite the hinge members 26 on the closure baseportion 14 is a finger recess 30 that provides a user of the finishedcontainer with additional leverage for opening the flip-top closure ofthe container.

As shown in FIG. 2, an additional component is provided for combinationwith the preform 10 to create a finished container. The additionalcomponent is the closure top 40 of the flip-top closure. The closure top40 includes a generally flat, closed top surface 42. It also includes anouter skirt 44 extending nearly around the entirety of the top surface42.

The outer skirt 44 and top surface 42 are provided with hinge openingsor notches 46. The hinge openings 46 are sized and spaced to coordinatewith the hinge members 26 of the closure base portion 14. Each of thehinge members 26 and hinge openings 46 are also provided withcoordinating structures to secure the hinge members 26 within the hingeopenings 46 while allowing rotational movement of the closure top 40relative to the closure base portion 14. In the illustrated embodiment,the inner surfaces of the hinge members 26 are provided with ballprotrusions 32. These ball protrusions 32 fit into detents 48 positionedin the inner side surfaces of the hinge openings 46 when the closure top40 is mated with the closure base portion 14. It will be readilyappreciated that the positioning of the ball protrusions 32 and detents48 may be reversed to be in the hinge openings 46 and hinge members 26,respectively, without impacting the functioning of the finished closure.In general, the detents 48 allow the rotation of the ball protrusions 32therewithin, thereby allowing the rotation of the closure top 40relative to the closure base portion 14.

Those of skill in the art will readily recognize that the specific hingestructure above is non-limiting and different types of hinge structuresmay be used in the preform of the present invention.

In one advantageous embodiment as shown in FIG. 2, the closure top 40may also incorporate a tamper-evident tab 50 positioned generallybetween the hinge openings 46. The tamper-evident tab 50 coordinateswith the depressed area 28 in the outer skirt 16 of the closure baseportion 14 to create a tamper-evident feature for the assembled flip-topclosure. More particularly, the tamper-evident tab 50 extends below thelevel of the outer skirt 44 of the closure top 40. Thus, thetamper-evident tab 50 will interfere with the rotationally movement ofthe closure top 40 relative to the closure base portion 14 and must beremoved in order for a user to open the flip-top closure. Once removed,there is no means for reattaching the tab 50 to the closure top 40. Theresulting absence of the tab 50 provides an indication to a user thatthe flip-top closure has previously been opened.

The depressed area 28 is sized to match the dimensions of the tab 50.The coordinated fit of the depressed area 28 and tab 50 allows the tab50 to fit within the general confines of the depressed area 28 such thatthe tab 50, the outer skirt 44 of the closure top 40, and the outerskirt 16 of the closure base portion 14 present a generally consistentcylindrical appearance until the tab 50 is removed, which is desirablefor enhanced aesthetic performance of the finished container.

FIGS. 5 and 6 further illustrate the details of the closure base portion14 and closure top 40 as described above. FIG. 6 further illustratesfeatures of the underside of the closure top 40. In addition to thestructures described above, the closure top 40 includes an inner skirt52. The inner skirt 52 coordinates with the collar 20 of the closurebase portion 14 to create a seal when the flip-top closure is closed.FIG. 6 also illustrates the hinge openings 46 and outer skirt 44 of thesecond closure portion 40 from a different perspective.

FIG. 7 illustrates an alternate embodiment of a preform 10′. The preform10′ of FIG. 7 is similar in arrangement to the preform 10 of FIGS. 2-6.Therefore, FIG. 7 includes reference numerals identifying thecorresponding elements of preform 10′. However, preform 10′ lacks anouter skirt (ref. 16 in FIGS. 2-6) with its closure base portion 14′.Instead, the closure base portion 14′ includes only central opening 18′that communicates with the hollow interior of the container portion 12′of the preform 10′. Surrounding the central opening 18′ is a slightlyupwardly extending collar 20′. Surrounding the collar 20′ is a generallyflat, first horizontal surface 22′. Outside of this first horizontalsurface 22′ is a second surface 24′ that lies slightly below the levelof the first surface 22′. The closure base portion 14′ also includes amatching pair of hinge members 26′ extending upward from the uppersurfaces of the closure portion 14′. These hinge members 26′ provide aconvenient point of attachment for the closure base portion 14′ with atop portion of the closure.

In general, a preform as described above and resulting container arecreated as follows. The preform is formed by injection molding athermoplastic material onto a core pin. The molten polymer is fed into amanifold where it is injected through nozzles into a hollow, heatedpreform mold. The preform mold forms the external shape and is clampedaround the core pin which forms the internal shape of the preform. Thepreform is then transferred on the core pin into a blow molding station.The core pin opens and allows compressed air into the preform, whichinflates it to the finished article shape. After a cooling period theblow mold opens and the core pin is rotated to the ejection position.The inflated preform/new container is stripped off the core pin and thesecond closure portion is attached to the first closure portion. Thecontainer is typically leak-tested prior to packing. The preform andblow molds can have several cavities depending on the article size andthe required output.

The preferred embodiment of the invention has been described above toexplain the principles of the invention and its practical application tothereby enable others skilled in the art to utilize the invention in thebest mode known to the inventors. However, as various modificationscould be made in the constructions and methods herein described andillustrated without departing from the scope of the invention, it isintended that all matter contained in the foregoing description or shownin the accompanying drawings shall be interpreted as illustrative ratherthan limiting. Thus, the breadth and scope of the present inventionshould not be limited by the above-described exemplary embodiment, butshould be defined only in accordance with the following claims appendedhereto and their equivalents.

What is claimed is:
 1. A preform for blow molding a plastic containerwith a flip-top closure, comprising: a container portion; a flip-topclosure base portion integrally molded with said container portion, saidflip-top closure base portion further comprising an integrally moldedfirst hinge structure, said hinge structure arranged for matingengagement with a second hinge structure of a flip-top closure top, andwherein said flip-top closure base portion further comprises a skirtextending downward from said upper surface of said flip-top closure baseportion and a depressed area in an outer surface of said skirt, saiddepressed area positioned between said pair of hinge members andarranged for engagement with a tab structure on said flip-top closuretop.
 2. The preform for blow molding a plastic container as set forth inclaim 1, wherein said first hinge structure further comprises a pair ofhinge members extending from an upper surface of said flip-top closurebase portion.
 3. The preform for blow molding a plastic container as setforth in claim 2, wherein each of said hinge members further comprisesone of the structures selected from the group comprising a detent and aball protrusion to facilitate mating engagement with said second hingestructure of said flip-top closure top.
 4. A blow-molded, plasticcontainer, comprising: a blow-molded container body; and a flip-topclosure base portion integrally molded with said container body in apreform, said flip-top closure base portion further comprising anintegrally molded first hinge structure; a flip-top closure top furthercomprising a second hinge structure, said first and second hingestructures arranged for mating engagement to rotatingly connect saidflip-top closure top with said flip-top closure base portion; and saidflip-top closure base portion further comprises a first outer skirtextending downward from an upper surface of said flip-top closure baseportion and a depressed area in an outer surface of said skirt; saidflip-top closure top further comprises a second outer skirt extendingdownward from a top surface of said flip-top closure top and a tabstructure extending downward from said top surface and extending belowthe bottom of said second outer skirt; and wherein said depressed areaand said tab structure are provided with generally matching dimensionsand are arranged for engagement with one another when said flip-topclosure top and flip-top closure base are initially connected in aclosed position.
 5. The blow-molded, plastic container as set forth inclaim 4, wherein said first hinge structure further comprises a pair ofhinge members extending from an upper surface of said flip-top closurebase portion.
 6. The blow-molded, plastic container as set forth inclaim 5, wherein said second hinge structure further comprises a pair ofhinge openings in said flip-top closure top, each of said hinge openingsbeing arranged to receive one of said hinge members of said flip-topclosure base portion.
 7. The blow-molded, plastic container as set forthin claim 6, wherein each of said hinge openings further comprises astructure selected from the group comprising detents and ballprotrusions.
 8. The blow-molded, plastic container as set forth in claim5, wherein each of said hinge members further comprises a structureselected from the group comprising a detent and a ball protrusion. 9.The blow-molded, plastic container as set forth in claim 4, wherein saidfirst hinge structure further comprises a pair of hinge membersextending from an upper surface of said flip-top closure base portion;said second hinge structure further comprises a pair of hinge openings,each of said hinge openings being arranged to receive one of said hingemembers of said flip-top closure base portion; and said depressed areapositioned between said pair of hinge members and said tab structurepositioned between said hinge openings.